1. Field of the Invention
The present invention relates to an H.264 codec IC (integrated circuit) and an H.264 codec method that perform compression/expansion processing compliant with H.264 which is a standard for the compression/expansion of main video data and defined by ITU (International Telecommunication Union), and a DVD (digital versatile disc) playback apparatus that uses such an IC, and more particularly, to an H.264 codec IC and an H.264 codec method dealing higher-definition data, and a DVD playback apparatus that uses such an IC.
2. Description of the Related Art
The standards for an HD (high definition)-DVD that is a next generation DVD are currently under drafting process. It is expected to be highly possible that H.264 will be adopted as a codec (compression/expansion) of main video data in the next generation DVD. Note that in the following description, compression and expansion will be also expressed as encoding and decoding respectively.
Japanese Patent Application Laid-open No. 2000-341258 (Patent document 1) discloses a technique of establishing synchronization of video and multichannel audio in a compression process of data codec. Such encoding enables a decoding side to playback the video and the audio at the proper timing. Further, Japanese Patent Application Laid-open No. Hei 11-196077 (Patent document 2) discloses a technique of establishing frame synchronization of data output in a data decoding process.                [Patent document 1] Japanese Patent Application Laid-open No. 2000-341258        [Patent document 2] Japanese Patent Application Laid-open No. Hei 11-196077        
Since a codec IC for decoding respective data of main video, sub-video and audio recorded on a next-generation DVD needs a larger circuit scale, it is highly possible that codec integrated circuits that are formed individually for the respective data will be used during initial phases. In this case, the output timing of each decoder is determined based on a presentation time stamp (PTS) written on a header of each packetized data. As a prerequisite for this, each decoder is supplied with a value of a system time clock (STC).
However, if the time required for the supplied value of the STC to be reflected in each decoder is different, there naturally occurs a difference in the timing among the respective decoded data of the main video, the sub-video, and the audio. Incidentally, neither of the afore Patent documents 1, 2 mentions such a problem.